The present invention relates to an oxide superconductor which may be used for coils of superconductor magnets, superconducting cables and superconductor devices such as superconductor memory.
Recently, various oxide superconductors which exhibit very high critical temperatures (Tc) have been discovered. For producing a thin film of an oxide superconductor of, for example, a Ba-La-Cu-O system, attempts have been made by forming the thin film on a substrate of sapphire or other conventional materials. Such a superconductor has been formed by high frequency sputtering, using a target made of the superconductor material, or other conventional techniques.
Superconductors thus formed are exposed to the atmosphere and hence have, a problem in that their performance deteriorates over a period of time since oxygen in them escapes into the atmosphere, and since components, such as vapor, of the atmosphere react with them.
Accordingly, it is an object of the present invention to provide an oxide superconductor which reduces the above drawback.